About Brinch

Description

Ask Me Anything: 10 Responses To Your Questions About Audi G28
How to Replace an Audi G28 Engine Speed Sensor


In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC, and the position of the camshaft, in order to activate the spark and injectors.

If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).

It can be a bit difficult to test because there are several connector pins, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is functional, it should read approximately 1000 ohms. Look for signs of coolant, or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing any more. Today, i pulled out the spark plugs, 3 were drenched with gazoline the fourth one was dry. When i crank the engine without sparks, i place a tissue on the top of each hole in the injector, the 3 drenched with gazoline jump out but the 4th one stays closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of that is -49c even after unplugging it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do. audi a4 car key replacement feel like i've pretty much all other possibilities out. But i'm worried that I may have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. Testing them is easy to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They should be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, for example. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go bad you will get codes on the diagnostic scanner that could cause engine shut down.

A failing G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, or a misfire while in the gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these signs. The good news is they are quite affordable and easily accessible particularly in the case of an Bosch sensor, like ours. If you prefer, GM's version of this part is an option.

5. Tachometer

A failing engine speed sensor could be the reason behind numerous issues with your vehicle. It is a crucial part of your Audi's transmission, because it communicates to the ECU about how fast or slow the car's crankshaft is spinning. If the sensor fails, it can disrupt the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig, and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect a resistance of approximately 1000 ohms in these areas. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du You may also find some good ones in wrecking yards.